Preclinical studies have suggested a link between the neuropharmacology of oxytocin (OT) and changes in behavior, cognition, and neurochemistry associated with schizophrenia. To test these observations clinically, we measured the cerebrospinal fluid OT concentrations of 40 schizophrenic and 15 control subjects using a competitive radioimmunoassay. The CSF OT concentrations of neuroleptic-treated patients were not statistically different from those of the neuroleptic-withdrawn group. No significant differences were found between the mean values of the schizophrenic group and the healthy group.